USA and Rocket Base stage theme music in this version have different instrument instead of original (unlike other stage theme and boss theme, which have different arrangement)
*Lean:* Control, hostile aircraft entered the exosphere and it seems to be heading towards moon. Please advise. *Control:* Return to base at once Strikers. We will strap your propeller driven fighters to 1940s-tech rockets and send you into the space. *Lean:* ...
I'm pretty sure it was the Soundtrack because I was playing on the USA and Canada version, and the music is probably unused in the NTSC America version.
There are ports for ps1 saturn ps2 and switch and windows. Just be sure to get this exact version cause in america the first 1945 was not ported to ps1 and it is just called like that but it is 1945 II , you ill notice cause of the stages and airplanes. look for the exact stages of here.